chalcogrammus

Chalcogrammus is a genus of marine ray-finned fishes in the family Gadidae, order Gadiformes. The circumscription of the genus has varied in taxonomic treatments; some authorities accept Chalcogrammus as a valid genus containing a small number of cod-like species, while others treat it as a synonym of Gadus or Theragra, transferring its species to those genera.

Geographic distribution and habitat: The taxa historically assigned to Chalcogrammus are associated with cold northern waters of the North Pacific and Arctic Oceans, including regions around Alaska, the Bering Sea, and nearby continental shelves. They inhabit demersal habitats on continental shelves and slopes, often in relatively shallow to moderately deep waters.

Biology and ecology: As members of Gadidae, species in this genus are typically predatory, feeding on small fish and invertebrates. They are generally elongated and show the typical dorsal-fin arrangement seen in cods; morphology can vary with taxonomy, and some species may exhibit features such as chin barbels that aid in detection of prey.

Taxonomic notes and example: The best-known species historically linked with Chalcogrammus is the Alaska pollock, originally described as Gadus chalcogrammus and later reassigned to Theragra. This history illustrates how genus-level classifications within Gadidae have shifted with phylogenetic studies and revisions to the family’s taxonomy.

See also: Alaska pollock, Theragra, Gadus.